Graeme McDowell faces a five-hole sprint for what could be a massively important win in the OHL Classic at Mayakoba in Mexico today.

The Co Antrim man fired six birdies in 13 holes to grab a share of the lead with Scotland's Russell Knox before the final round was suspended until 8am today.

The Rathmore man, 36, chasing his first PGA Tour win since 2013 and hoping to rise as high as 61st in the world after a miserable year saw him fall 60 spots to 85th

Having dropped five shots on the first hole in three rounds, sandwiching a bogey between two doubles, McDowell opened with a par and added three more on a stop-start dat at El Camaleon Golf Club in Playa del Carmem.

The fourth round was delayed 3 1/2 hours by thunderstorms that left pools of water across the course but McDowell made three birdies in a row from the seventh to go out in 33 before picking up three more birdies in his last four holes at the 10th, 12th and, crucially, the par five 13th, where he elected to finish when the horn sounded to suspend play because of darkness. 

That helped him join Knox, who was still on the 13th hole, on 19 under, two shot ahead of Jason Bohn, who chipped in for eagle on the fifth hole for an early lead but dropped two shots and was at 17 under through 12 holes.

The final round was to resume at 8 a.m. today, making it the first time in 10 years that back-to-back PGA TOUR events finished on Monday because of rain. 

The Sanderson Farms Championship in Mississippi had a marathon finish last Monday because of the weather.

With soft conditions, there figures to be little room for error when Mayakoba ends on Monday.

Scott Brown (through 14 holes) and Derek Fathauer (12 holes) were four shots behind. 

Fathauer, trying to make it six straight PGA TOUR events with a first-time winner, had a one-shot lead starting the final round but had only one birdie against two bogeys to fall back.

Knox is coming off his first win last week in Shanghai at the World Golf Championships-HSBC Champions, and he was so exhausted that he considered pulling out this week. Instead, he continued his around-the-world journey to Mexico. He can become the first player since Camilo Villegas in 2008 to win his first two TOUR titles in successive weeks.

The 30-year-old from Scotland ran off four straight birdies starting at No. 3, and then stuffed his approach just short of the pin on the par-3 eighth and went out in 31. He picked up his sixth birdie on the 11th hole.

Along with three straight birdies on the front nine, McDowell parred the opening hole at El Camaleon. He had played the first in 5 over through three rounds -- two double bogeys and a bogey. This time, he hit 3-wood off the tee.

Justin Leonard, Patrick Rodgers and Freddie Jacobson, and PGA TOUR rookie Harold Varner III were at 13 under, six shots behind.